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Overview study from the AWI on plastic pollution in the Arctic

Although the Arctic has a very low population, it has, according to an international overview study from the Alfred-Wegener Institute (AWI), a similar amount of plastic pollution as other regions of the world. The study was published in the specialist magazine "Nature Reviews and Environment Research". According to the report, the research results show that plastic litter is discharged into the sea and to the Arctic for example via rivers, the air and shipping. Shipping in particular is an important discharge source. The waters of the Arctic, the sea floor, beaches, rivers and ice and snow are, according to the study, being increasingly polluted by microplastic.

 

For the study, the AWI team headed by marine biologist Melanie Bergmann, together with researchers from Norway, Canada and the Netherlands, evaluated and summarised a total of 198 sources from the Litterbase database. This contains studies, field tests and models on the occurrence, discharges and effects of plastic waste in the Arctic region. What is new is the broad pan-Arctic perspective of the overview study, which goes beyond earlier research approaches. The report describes sources, distribution and consequences of pollution by plastic litter, including microplastic. The report also identifies knowledge gaps and the further need for research, and describes measures for tackling Arctic pollution due to plastic waste.

 

Local and distant discharge sources

With regard to the discharge sources, the authors of the study distinguish between land-based and sea-based sources of local and distant origin. Their analysis of the discharge pathways is based on data from 36 scientific studies from the Litterbase database. Most model simulations and data, says the study, point to the fact that a considerable proportion of the plastic discharges get into the Arctic via the north Atlantic and north Pacific. Some of the pollution is, according to the reference studies, attributable to waste and debris stemming from local fishing, waste dumps, effluent and also industrial offshore activities. But also regions further away are listed as a key source: Microplastic, for example, is transported into the region through the air. A large amount of plastic waste is also likely to get into the Arctic region from lower latitudes via rivers and marine currents. As part of the study "The widespread environmental footprint of indigo denim microfibers from blue jeans", Kerstin Athey and her research team found, for example in the year 2020, around 1,930 fibres per kilogramme dry weight in sediments of the Canadian Arctic. The scientists describe this quantity of microplastic particles as substantial, and say it is attributable to discharges from effluent from the textile industry coming from further south.

 

However, according to a 2016 study entitled "Microlitter in sewage treatment systems: A Nordic perspective on waste water treatment plants as pathways for microscopic anthropogenic particles to marine systems" compiled by a Danish research group, some of the microplastic could also stem from local sources. The study examined the emissions from a sewage treatment plant in the Icelandic capital of Reykjavik. Six million microplastic particles – approx. 1,500 particles per cubic metre – had entered the ocean there every hour. Further potential local sources for microplastic in the Arctic are, according to the AWI research team, also particles originating from marine paints and from vehicles that are used on the ice. The study notes that microplastic discharges can also stem from wastewater from shipping (so-called “grey water”) that is being increasingly released as a result of the mounting tourism and, as a result, the increasing number of cruise vessels on the oceans. Another important local source of plastic waste cited by the study is plastic waste from households. Because the objects found there such as plastic bags or bottles are also used on ships, the researchers were unable to clearly assign such plastic litter to land-based or sea-based sources.

 

Pollution through macro and microplastic

The available data show, according to the overview study, that microplastic with up to 1,287 pieces per cubic metre and plastic waste with up to 7.97 pieces per square kilometre, is widespread in the Arctic surface waters. Also the Arctic sea ice shows, according to sources referenced in the study, a high level of contamination by microplastic, namely 31.75 to 12 million particles per cubic metre. The data indicate that plastic waste is transported through the drifting of sea ice, and can thus become widely distributed in the region. Microplastic from the surface of the sea is trapped in the ice. In the spring and summer, the sea ice breaks up and the microplastic gets, together with the pieces of ice, into warmer climes, where the ice melts and releases the plastic particles into the water. According to the respective studies, macro and microplastic was also found on the sea floor. The number of larger plastic particles on the sea floor fluctuates, says the study, between 0 and 24,500 pieces per square kilometre and, from 2004 to 2017 for example, increased in the deep sea of the Fram Strait between Spitzbergen and the northeast of Greenland from 813 to 5,970 pieces per square kilometre. The microplastic concentration in the Arctic waters is, according to the evaluated reference studies, up to 16,041 particles per kilogram of sediment, and is thus among the highest measured concentrations worldwide. The report does, however, also point out that the sampling and analysing methods used in the various studies sometimes differ considerably, because there are currently only a few standardised or harmonised procedures. For example, different size detection limits for microplastic particles in the various studies could have led in some cases to very different measurements.

 

Effects on eco systems and climate

The effects of environmental pollution on Arctic organisms due to plastic waste are, according to the AWI study, not yet adequately researched. They are nevertheless assumed to be just as serious as in better studied regions. When Arctic creatures eat microplastics, it can have similar consequences as it does for organisms in other parts of the world, namely stunted growth or limited reproduction. Apart from this, the research team suspects, plastic waste in the Arctic could also accelerate climate change. "Initial studies provide indications that trapped microplastic alters the properties of sea ice and snow," explains marine biologist Bergmann. Dark particles in the ice could thus lead to a situation in which more sunlight is absorbed and the ice melts more quickly as a result. This, in turn, can intensify global warming. In order to reduce the release of plastic waste into the environment, the scientists consider it necessary to reduce the global production of plastic waste through the introduction of mandatory targets in international agreements, similar to the Paris agreement. In addition, there should in their opinion not only be an improvement in the systems for communal waste collection and management, but measures should also be taken to provide for the circular use of plastics and the utilisation of sustainable alternatives.

 

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